Road design

The Guide to Road Design Part 4B: Roundabouts provides road designers and other practitioners with guidance on the geometric design of roundabouts. Part 4B covers design principles and procedure, and provides guidelines for all the key elementsthus enabling practitioners to develop safe and efficient layouts. It also provides information on pedestrian and cyclist treatments at roundabouts and related topics such as pavement markings, signs, and landscaping. However, designers should refer to all other relevant parts of the Guide to Road Design and to the Guide to Traffic Management – Part 6: Intersections, Interchanges and Crossings (2007) which covers traffic management and road use aspects of roundabouts.Part 4B includes a new design method for roundabouts that focuses on the entry curvature to achieve a reduction in vehicle approach speeds rather than applying the ‘deflection method’ used in previous Australian guides.